Embodiments according to the invention create an audio signal decoder for providing a decoded representation of an audio content on the basis of an encoded representation of the audio content.
Embodiments according to the invention create an audio signal encoder for providing an encoded representation of an audio content comprising a first set of spectral coefficients, a representation of an aliasing-cancellation stimulus signal and a plurality of linear-prediction-domain parameters on the basis of an input representation of the audio content.
Embodiments according to the invention create a method for providing a decoded representation of an audio content on the basis of an encoded representation of the audio content.
Embodiments according to the invention create a method for providing an encoded representation of an audio content on the basis of an input representation of the audio content.
Embodiments according to the invention create a computer program for performing one of said methods.
Embodiments according to the invention create a concept for a unification of unified-speech-and-audio-coding (also designated briefly as USAC) windowing and frame transitions.
In the following some background of the invention will be explained in order to facilitate the understanding of the invention and advantages thereof.
During the past decade, big effort has been input on creating the possibility to digitally store and distribute audio content. One important achievement on this way is the definition of the International Standard ISO/IEC 14496-3. Part 3 of this Standard is related to a coding and decoding of audio contents, and sub-part 4 of part 3 is related to general audio coding. ISO/IEC 14496, part 3, sub-part 4 defines a concept for encoding and decoding of general audio content. In addition, further improvements have been proposed in order to improve the quality and/or reduce the necessitated bitrate. Moreover, it has been found that the performance of frequency-domain based audio coders is not optimal for audio contents comprising speech. Recently, a unified speech-and-audio codec has been proposed which efficiently combines techniques from both words, namely speech coding and audio coding. For some details, reference is made to the publication “A Novel Scheme for Low Bitrate Unified Speech and Audio Coding—MPEG-RM0” of M. Neuendorf et al. (presented at the 126th Convention of the Audio Engineering Society, May 7-10, 2009, Munich, Germany).
In such an audio coder, some audio frames are encoded in the frequency-domain and some audio frames are encoded in the linear-prediction-domain.
However, it has been found that it is difficult to transition between frames encoded in different domains without sacrificing a significant amount of bitrate.
In view of this situation, there is a desire to create a concept for encoding and decoding an audio content comprising both speech and general audio, which allows for efficient realization of transitions between portions encoded using different modes.